A DNA-directed cell-free system for protein synthesis is being used to quantitatively analyze the factors necessary for regulation of genes associated with the lac and ara operons of E. coli. Factors which are being studied include the CAP protein, the ara C protein, the Rho y factor, which may be important in termination, ppGpp which probably stimulates transcription, putrescine which may be generally important to the transcription or translation process and a protein factor required for polarity. Regulation of DNA synthesis will be examined under similar circumstances.